Do you ever wish you had a way to hide certain contacts in your address book? Maybe you want the ability to completely hide entire SMS or e-mail conversations from prying eyes? BlackBook, a popular BlackBerry application, allows you to do just that. This simple-to-use app keeps your most valued information hidden and secure.

To use BlackBook you will need a BlackBerry running OS 4.5 and above. You can purchase BlackBook from BlackBerry App World; it will set you back $1.99. Once you download and install the app, the first thing you will notice is the lack of an app icon on your BlackBerry for BlackBook. The app icon was intentionally left out. You may also notice that the app installs under an assumed name of Clock. These are the first two steps taken to ensure that your information stays private.

Screenshot by Jason Cipriani

To launch the app you will need to be viewing your BlackBerry's home screen and press the End key five times. Once you have launched BlackBook you can view your hidden contacts and conversations.

Screenshot by Jason Cipriani

If you already have contacts in your native BlackBerry address book that you want to make private, you can import them into BlackBook, removing them from your address book.

Screenshot by Jason Cipriani

Once you have contacts imported or entered into BlackBook, the application will constantly monitor any incoming and outgoing data, constantly comparing it to the contacts in your BlackBook. Under the Options portion of the app you can designate the types of messages you want the app to monitor. Also notice under Options you can customize the launch key.

Screenshot by Jason Cipriani

If an e-mail or SMS comes in from one of your BlackBook contacts, that message will never make it to your default BlackBerry inbox. Instead, the message will be kept within the BlackBook app itself, keeping everything private and secure. Your BlackBerry will only vibrate when you receive a new message. There is also an option to have a customizable alert display for new messages. For example, a default message of "System Memory Low" will pop up on your screen whenever there is a new alert in BlackBook.

BlackBook also has a Stealth Mode. When activated, Stealth Mode will send any incoming calls of contacts in your BlackBook directly to voice mail. You can also enter an alias for contacts. Should you get a call from a contact with an alias, instead of the Caller ID displaying the contact name, the alias entered in BlackBook will be displayed.

The options and features of BlackBook run deep and are sure to help anyone keep their information private, whatever their motive. For more information about BlackBook you can visit Mblware's Web site.